My mk4 Golf 1.6 SE....

[bmkev]

....has a strange problem. It keeps on running fast for some reason .
Every now and again it will rev to around 1500-2000rpm for no apparent reason. I have cleaned the throttle body, checked the MAF (appears ok) and checked and cleaned all engine sensor connections. Funny thing is that when it's running fast if you release the clutch while in gear with you're foot on the brake to reduce the rpm. What ever rpm you reach it will stay at when you release the clutch i.e normal idle speed.
I have also removed the engine temp sensor and checked it with an ohm meter as I warmed and cooled it indoors. The resistance seemed to alter as it should.

I have also tried resseting the ECU and this also made no real diffrence.I am now miffed. Like I said it's not all the time although it's doing it now and driving me mad.

BTW hi to you all I am new and would love some help.
Cheers...

[shooey88]

have you done basic settings with a vagcom correctly after you cleaned the throttle body....just cleaning the throttle body will not solve the problem. you need to correctly do basic settings. sometimes the throttle body are stubborn and wont set correctly. disconnecting the battery for a few minutes then reconnecting then trying to reset basic settings is a good idea. make sure u have car up to temperature about 90.c also when doing basic setting on throttle body. an air leak can cause a lean mixture creating a fluctuating idle aswell so check the pipe going to the throttle body for a hole in it. this is common and people keep doing throttle body cleans but it dosent solve the problem due to the air leak coming from the pipe to the throttle body. its a small black pipe coming from the larger air filter pipe.

[bmkev]

Cheers mate I'll try it all again with you're advice.

[bmkev]

Just an update for you all. It was the engine temp sensor. Replaced it and now the motor runs perfect.